How Do Pilots Turn On an Airplane?

If you’re like many people, you may wonder: “Does an aircraft have a key?” Or more specifically, do aircraft have keys for ignition? For large planes, the answer is no. In the case of smaller private jets, some of them may use keys for ignition and doors but not all.

When pilots start the engines of an aircraft, specifically most passenger jets, they do not insert a key into the ignition. To provide power to the aircraft, they need to perform a specific startup procedure.

Powering the plane engine

To power a commercial jet, the pilot must operate a series of buttons, switches, and knobs successively. This turns on the Auxiliary Power Unit (APU) or the Ground Power Unit (GPU) — devices that are used to provide electrical power to the plane while also generating essential air pressure to the engines.

When you’re in the cabin, you may notice the air-conditioning system turning off and the lights dimming or flickering. This happens because the APU is directing air from the plane into the engines. The cabin lights get dimmer also because the APU must use electricity to power all vital systems of the aircraft.

Once the APU bleeds enough air to the starter, the engines will start spinning. The RPM of the engines must be monitored and when they reach a required frequency, fuel will be introduced. After that, the RPM will be monitored once again and when it reaches another set frequency, then the aircraft engine has successfully been turned on.

Conclusion

Basically, commercial airplanes do not have ignition keys simply because gaining access to the aircraft and getting it started is already a solid security system that is difficult, if not impossible, for common people to get through.

While the process above is highly generalized, it’s already a good and informative answer when someone asks you “How do Pilots start a plane?” Starting an aircraft is quite elaborate and requires specific know-how.